Reception system for multiple-tuner television enabling to automatically connect each tuner to at least an antenna, whatever the number of antennae it comprises

ABSTRACT

A system comprising a first converter linked to a first tuner and optionally, to a second tuner via switching means, optionally a second converter linked to the second tuner means for detecting whether the second converter is in service and means suitable for actuating the switching means in such a way as to link the second tuner to the second converter when one detects that the latter is in service and, in the converse case, to link it to the first converter.

This application claims the benefit, under 35 U.S.C. §365 ofInternational Application PCT/FR02/00094, filed Jan. 10, 2002, which waspublished in accordance with PCT Article 21(2) on Jul. 25, 2002 inFrench and which claims the benefit of French patent application No.0100605, filed Jan. 17, 2001.

The invention relates to a reception system for television comprising atleast two tuners each furnished with at least one input and one output,a first RF low signal noise converter linked at least to the first inputof the first tuner, optionally at least one second RF low signal noiseconverter, and means for switching the input of the second tuner bychoice over to the second converter or over to the first converter.

Such a system is generally used for the reception of television programsbroadcast by satellite.

BACKGROUND OF THE INVENTION

In the case of satellite television, the converters are generally called“LNBs”, the abbreviation standing for “Low Noise Block”; when the systemcomprises two converters, they are generally each placed at the centerof a satellite antenna and thus there are two antennas: however, theymay sometimes be placed at the center of the same satellite antenna,according to a so-called “twin LNB” configuration.

The document EP 0314931 (BRIONVEGA) describes a system comprising aplurality of converters and antennas, a single tuner (“satellitereceiver” referenced 21), and means (referenced 29) for switching theinput of this tuner by choice over to one or other of the plurality ofconverters (referenced 4, 7).

In the case of a system utilizing two converters and two tuners, thesimplest configuration consists in connecting a converter to the firsttuner and the other to the second tuner; according to a more complexconfiguration, the first converter provides a signal to be split on theone hand permanently to the first tuner and on the other hand optionallyto the second tuner, according to the position of these switching means;such a system then generally comprises:

-   -   switching means exhibiting two possible positions, one for        switching the input of the second tuner over to the second        converter as in the simplest configuration, the other for        switching the input of the second tuner over to the first        converter,    -   splitting means (the so-called “splitter”) for splitting the        signal delivered by the first converter to two outputs, one of        which is permanently linked to the input of the first tuner, and        the other of which is linked to the switching means; these        splitting means are generally incorporated into the first tuner,        so that this tuner then exhibits, in addition to the input for        gathering the signal from the first converter, an output for        duplicating this signal to another tuner.

A two-tuner system as described above may have the followingapplications:

-   -   it allows the viewer to watch a television program picked up by        the first converter and the first tuner, while recording another        television program processed by the second tuner; such an        application is described in particular in patent application        EP300193—THOMSON.    -   it allows the viewer to watch a main image of a television        program arid to inlay a secondary image of another television        program into this image; such an application is described in        particular in patent application U.S. Pat. No.        5,557,338—THOMSON.

By virtue of the switching means of the system described hereinabove,the system can therefore be used, as described hereinabove, to receivetwo television programs simultaneously, whether these programs originatefrom two different transmitting sources via the two converters of thesystem, or whether these programs originate from the same transmittingsource via just the first converter of the system:

-   -   in the first case of different sources, the switching means are        actuated in such a way that the input of the second tuner is        linked to the second converter,    -   in the second case where the source is identical, the switching        means are actuated in such a way that the input of the second        tuner is linked to the first converter via splitting means as        described hereinabove.

For applications of this type, it is then necessary to actuate thesystem switching means, depending on whether the two programs originatefrom the same source or from different sources.

To actuate the switching means, one merely needs to change thearrangements for plugging in the input of the second tuner.

To avoid this manual operation, it is also possible to provide switchingmeans which can be actuated remotely, for example with the aid of aremote control; such switching means are described (and referenced 29)in the document EP 0314931 already cited and are actuated remotely bythe keypad (referenced 23) of a remote control (see column 5, lines 3 to6).

The intervention of an operator for the actuation of the switching meanshas drawbacks, related for example to the risk of a keying error or tothe need, for the operator, to know whether the two programs are or arenot broadcast by the same source.

The aim of the invention is to avoid these drawbacks.

Document U.S. Pat. No. 6,009,304 describes a system comprising two RFlow signal noise converters suitable for delivering by choice a leftpolarized signal (“L”) and/or a right polarized signal (“R”); eachconverter comprises a low noise amplifier (“LNA”), a bandpass filter(“BPF”), a mixer (“MIX”) for converting the incoming signal into anintermediate frequency signal, and an intermediate frequency amplifier(“IF Amp”); between the mixer (“MIX”) and the amplifier (“IF Amp”), thesystem comprises means (“S.W.”) for switching the input of eachamplifier (“IF Amp”) by choice over to the output of the mixer of thefirst converter or/and over to the output of the mixer of the secondconverter; the system comprises means for driving the switching means asa function of the value of the voltages applied to the output of theconverter (see claim 3+column 1, lines 40 to 60); unlike in the case ofthe reception systems described above, the state of the switching meansis, at this juncture, independent of the state, in service or otherwise,of the converters; the system finally comprises means suitable forputting one or other of the converters out of service by removing thepower supply to its intermediate frequency amplifier (“IF Amp”), when itis detected that the output of this amplifier is not loaded (claim 1);the output of an amplifier is considered not to be loaded when a voltageof 0 V or less than the voltage for driving the switching means ismeasured (column 5, lines 29 to 35).

According to this document, the same means of detection serve to driveswitching means and means for placing out of service; the detectionmeans are not suitable for detecting whether one or other of theconverters is in service; thus, this document does not teach anysolution of a kind as to avoid the aforesaid drawbacks.

BRIEF SUMMARY OF THE INVENTION

To avoid the aforesaid drawbacks, the subject of the invention is areception system for television comprising a plurality of tuners eachfurnished with at least one input and one output, at least one RF lowsignal noise converter linked to an input of a tuner of said plurality,optionally at least one other RF low signal noise converter, and meansfor switching the input of at least one other tuner of said plurality bychoice over to a converter which is not yet linked to a tuner of saidplurality or over to a converter already linked to a tuner,characterized in that it comprises means for detecting whether theconverter not yet linked is in service or is not in service, and meanssuitable for actuating said switching means in such a way as to linksaid input of this tuner to the not yet linked converter when saiddetection means detect that the latter is in service and to link saidinput of this tuner to the converter already linked to another tunerwhen said detection means detect that the converter not yet linked isnot in service.

Other advantageous characteristics of the system according to theinvention are defined in the dependent claims.

The subject of the invention is in particular a reception system fortelevision comprising at least two tuners each furnished with at leastone input and one output, a first RF low signal noise converter linkedat least to the first input of the first tuner, optionally at least onesecond RF low signal noise converter, and means for switching the inputof the second tuner by choice over to the second converter or over tothe first converter characterized in that it comprises means fordetecting whether the second converter is in service or is not inservice, and means suitable for actuating said switching means in such away as to link the input of the second tuner over to the secondconverter when one detects that the latter is in service and to link theinput of the second tuner over to the first converter when one detectsthat this second converter is not in service.

The invention may also exhibit one or more of the followingcharacteristics:

-   -   the second converter being supplied with current when it is in        service, the means for detecting whether the second converter is        in service or is not in service rely on the detection of the        current on the supply circuit of this second converter.    -   the system also comprises a programmable microcontroller        suitable for controlling the switching means incorporating        software means adapted in such a way that the input of the        second tuner is connected:    -   to the second converter if the value of said current exceeds a        predetermined threshold,    -   to the first converter if the value of said current is less than        or equal to said threshold.

The subject of the invention is also a process for television receptionwith the aid of at least two tuners each connectable to correspondingmeans of reception, which may be placed in service or out of serviceindependently of one another, characterized in that it comprises thesteps consisting in, for at least one of the tuners,

-   -   detecting whether the means of reception corresponding to said        tuner are in service, and,    -   in the case where one detects that said means are in service,        connecting said tuner to these means.    -   in the case where one detects that said means are not in        service, connecting said tuner to other means already connected        to another tuner.

The invention may also exhibit the characteristic according to which,each of the means of detection requiring, when they are in service, apower supply producing a current greater than a predetermined thresholdvalue, one detects whether the means of reception are in service bycomparing the value of current produced by said power supply with saidthreshold value.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The invention will be better understood on reading the followingdescription, given by way of non-limiting example, and with reference tothe appended figures in which:

FIG. 1 illustrates a reception system for television according to afirst embodiment of the invention,

FIG. 2 illustrates an embodiment of software means able to drive theswitching means of the system according to the invention as described inFIG. 1,

FIG. 3 illustrates a reception system for television according to asecond embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, the reception system for television comprises afirst satellite antenna furnished with a first low noise converter 1,optionally a second satellite antenna furnished with a second low noiseconverter 1′, and a box 10.

The box 10 itself comprises:

-   -   a first tuner 2 furnished with a so-called “demodulated” output        and with an input 3 connected to the converter 1 via a socket 5        of the box: this first tuner here incorporates means (not        represented) for splitting the input signal both toward the        demodulation processing circuits specific to this tuner and        toward a so-called “duplication” output 4,    -   a second tuner 2′ furnished with an input 3′ and with a        so-called “demodulated” output,    -   means 6 for switching the input 3′ of the second tuner 2′ by        choice over to the second converter 1′ via another socket 5′ of        the box or over to the output 4 of the splitting means        incorporated into the first tuner,    -   means 7 of decoding the signals delivered by the tuners 2 and        2′, driven by a microcontroller 8; these decoding means, known        per se, will not be described in greater detail; they are        conventionally furnished with inputs 9 and 9′ each linked to the        so-called “demodulated” output of the tuners 2. 2′; they are        also furnished with outputs (not represented) linked for example        to display means and/or to recording means,    -   means 12 of control of the converter 1 which is plugged into the        socket 5 of the box and means 12′ of control of the converter 1′        which is plugged optionally into the other socket 5′ of the box;        these means of control have two main functions:        -   to supply power to each of the converters 1, 1′,        -   to determine, by way of the supply voltage level, the            direction of polarization, right “R” or left “L”, of the            television signal to be received by the converter; such a            function is described in detail in the document U.S. Pat.            No. 6,009,304 already cited (see in particular column 1);    -   These means of control 12, 12′ are suitable for injecting the        supply voltage for driving each converter 1, 1′ between the        socket of the box 5, 5′ of this converter and, as the case may        be, the switching means 6; thus plugged in upstream of the        switching means 6, they are capable of powering this converter        regardless of the state of these switching means. As illustrated        in FIG. 1, these means of control 12, 12′ may be driven by the        microcontroller 8.    -   The radiofrequency signals from each converter 1, 1′ are        superimposed on the supply voltage for driving this converter.

According to the invention:

-   -   the switching means 6 are controllable remotely by the        microcontroller 8,    -   the box 10 furthermore comprises means of current detection 11′        which are disposed on the supply circuit of the second converter        1′, here between the means of control 12′ and the socket 5′, and        which are suitable for delivering, to the microcontroller 8,        data relating to the value 1′ of this supply current,    -   the microcontroller 8 incorporates software means for control of        the switching means 6 adapted in such a way that the input 3′ of        the second tuner 2′ is connected:        -   to the second converter 1′ if the value of said current            exceeds a predetermined threshold,        -   to the output 4 of the splitting means incorporated into the            first tuner 2, that is to say indirectly to the first            converter 1 if the value of said current is less than or            equal to said threshold.

To implement the invention, these software means may for example beemployed according to the logic chart of FIG. 2:

-   -   in the first step called “Power On”, the microcontroller and the        other components of the box 10 are powered up conventionally,        and the means of control 12 of the converter 1 which is linked        to the socket 5 are activated,    -   in the second step called “Init”, and the state of the switching        means 6 is initialized in such a way that the socket 5′ of the        box is connected to the input 3′ of the second tuner 2′,    -   in the third step called “Read”, the means of control 12′ of the        converter 1′ which is optionally linked to the socket 5′ are        activated and the data transmitted by the means of current        detection 11 are gathered,    -   in the fourth step called “compare”, the value of current read I        in the previous step is compared with a predetermined threshold        value 10; for a conventional converter powered conventionally at        12.5 V or at 17 V depending on the polarity, vertical or        horizontal, of the television signal to be received, the value        of the supply current may reach the maximum value of around 350        mA; the predetermined threshold value is chosen for example to        be around 10% of this maximum value, i.e. here I₀=35 mA        approximately:        -   if I>I₀, then the fifth step consists in maintaining or in            restoring the state of the switching means 6 in such a way            that the socket 5′ of the box is connected to the input 3′            of the tuner 2′;        -   if I≦I₀, then the fifth step consists in establishing the            state of the switching means 6 in such a way that the output            4 of the splitting means incorporated into the first tuner 1            is connected to the input 3′ of the second tuner 2′;            preferably, in this case, the means of control 12′ are            deactivated so as to limit energy consumption and to avoid            any risk of short-circuiting at the level of the socket 5′;    -   on completion of the fifth step, we loop back to the third step        described above called “Read”; the looping rate can be adjusted        in a manner known per se as a function of the desired rate of        updating of the state of the switching means 6.

Thus, by virtue of the invention, the tuner 2′ is:

-   -   either linked to the second converter 1′ when one detects a        supply current to this converter via the socket 5′, that is to        say when the second converter 1′ is in service, that is to say        is plugged into the socket 5′ of the box 10,    -   or linked to the first converter 1 via the tuner 2, when one        does not detect any supply current via the socket 5′, that is to        say when the second converter 1′ is not in service, that is to        say is not plugged into this socket of the box 10.

Thus, by virtue of the invention, the two tuners are always operationaland connected to a source without any intervention from the viewer beingnecessary any longer, whether just one or two sources are connected tothe box 10; when just one source is connected via the socket 5, the twotuners are linked to this single source; when two sources are connected,each tuner is linked to a source.

According to a variant relating to the components of the box 10 themeans for splitting the signal delivered by the first converter areexternal to the tuner 1; such means are called splitters.

According to another embodiment of the invention described in FIG. 3,where the system again comprises two tuners 2 and 2′ here each furnishedwith a so-called “duplication” output 4, 4′, in addition to the elementsdescribed hereinabove, the system comprises:

-   -   switching means 6′ which make it possible to connect the input 3        of the first tuner 2 by choice to the first converter 1 via the        socket 5 or to the second converter 1′ via the socket 5′; the        means of control 12 of the converter 1 are plugged in upstream        of the switching means 6′ so as to be able to power this        converter regardless of the state of these switching means,    -   means of detection of current 11 on the supply circuit of the        first converter 1, which are positioned between the means of        control 12 and the socket 5 of the box 10, and are suitable for        delivering, to the microcontroller 8, data relating to the value        I′ of said current,    -   the microcontroller 8 incorporates software means for control of        the switching means 6′ adapted in such a way that the input 3 of        the first tuner 2 is connected:        -   to the first converter 1 if the value of said current I′            exceeds a predetermined threshold,        -   to the output 4′ of splitting means incorporated into the            second tuner 2′, that is to say indirectly to the second            converter 1′, if the value of said current is less than or            equal to said threshold.

The advantage of this variant is that, the system being perfectlysymmetrical, when a single source or a single converter is connected tothe box, one obtains the advantages of the invention regardless of whichsocket 5, 5′ this converter is connected to.

The invention applies also to television reception systems comprisingmore than two tuners, for example n tuners; the box then comprises ninput sockets connectable to an antenna, more precisely to a converter(since there may be several converters for the same antenna); inside thebox, suitable switching means make it possible to link, by choice atleast one of the tuners, or even each tuner, either to the socketcorresponding thereto when the latter is connected to a converter andwhen this converter is in service, or, in the converse case, to anothersocket corresponding to another tuner from the moment that this socketis itself connected to an in-service converter, so that, by virtue ofthe invention, all the tuners of the box are connected permanently toin-service converters and can be used simultaneously for displaying orrecording different television programs.

Thus, regardless of the number of antennas in the reception system—thisnumber being less than or equal to the number of tuners—the systemaccording to the invention makes it possible to automatically connecteach of the tuners to at least one antenna, without requiring theintervention of an operator, without any risk of error of connection,and without needing to know whether various programs are or are notbroadcast by the same source.

In the description hereinbelow, the detection of the placing in serviceor otherwise of a converter relies on the measurement of current,upstream of the means of control 12, 12′, in the radiofrequency linelinking the socket 5, 5′ capable of being connected to this converter tothe switching means 11, 11′; without departing from the invention, thissame measurement of current can be incorporated into the means ofcontrol 12, 12′ themselves.

Finally, without departing from the invention, means other than themeasurement of current produced by the power supply to the convertersmay be used to detect whether a converter not yet linked is or is not inservice.

1. A reception system for television comprising: a plurality of tunerseach furnished with at least one input and one output, a first RF lowsignal noise converter connected to an input of a first tuner of saidplurality of tuners, a second RF low signal noise converter, means forswitching the input of a second tuner of said plurality of tuners bychoice over to the second converter or over to the first converter,means for detecting whether the second converter is in service or is notin service, and means suitable for actuating said switching means insuch a way as to connect said input of the second tuner to the secondconverter when said detection means detect that the second converter isin service and to connect said input of the second tuner to the firstconverter when said detection means detect that the second converter isnot in service.
 2. The system as claimed in claim 1, wherein, the secondconverter being supplied with current when it is in service, the meansfor detecting whether this second converter is in service or is not inservice rely on the detection of a current on the supply circuit of thissecond converter.
 3. The system as claimed in claim 2, wherein itcomprises a programmable microcontroller suitable for controlling theswitching means incorporating software means adapted in such a way thatthe input of the second tuner is connected: to the second converter ifthe value of said detected current exceeds a predetermined threshold, tothe first converter if the value of said detected current is less thanor equal to said threshold.